1. Field of the Invention
This invention relates to a process for the catalytic hydrotreatment of a sulfur- and metal-containing hydrocarbon feedstock. More particularly, this invention relates to a process for the catalytic hydrotreatment of a sulfur- and metal-containing hydrocarbon feed which comprises contacting the feed with hydrogen and a catalyst having a specified pore size distribution in a manner such that the catalyst is maintained at isothermal conditions and is exposed to a uniform quality of feed. The process of the instant invention is particularly effective in achieving desired levels of hydrodesulfurization in the fraction of hydrotreated/hydrocracked petroleum resid product having a boiling point greater than 1000.degree. F.
2. Information Disclosure Statement
The use of catalytic hydrotreatment processes to treat hydrocarbon feedstocks, particularly petroleum residua, to achieve hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and hydrodemetalation (HDM) (particularly including removal of nickel compounds (HDNi), and vanadium compounds (HDV)), is well known to those skilled in the art. Many of these processes employ hydrotreating catalysts with specified proportions or ranges of proportions of pores having relatively small diameters (i.e. micropores, herein defined as pores having diameters less than 250A) and pores having relatively large diameters (i.e. macropores, herein defined as pores having diameters greater than 250A). Examples of such catalysts include the following:
U.S. Pat. No. 4,652,545 (Lindsley et al.) discloses a catalyst composition useful in the hydroconversion of heavy oils, the catalyst containing 0.5-5% Ni or Co and 1.8-18% Mo (calculated as the oxides) on a porous alumina support, having 15-30% of the Ni or Co in an acid extractable form, and further characterized by having a Total Pore Volume (TPV) of 0.5-1.5 cc/g with a pore diameter distribution such that (i) at least 70% TPV is in pores having 80-120A diameters, (ii) less than 0.03 cc/g of TPV is in pores having diameters of less than 80A, and (iii) 0.05-0.1 cc/g of TPV is in pores having diameters of greater than 120A. Lindsley et al. is distinguished from the instant invention in that its catalyst restricts the pore volume in pores with diameters .gtoreq.120A to 0.05 to 0.10 cc/g, whereas the catalyst employed in the instant invention typically contain 0.30 to 0.50 cc/g in this region;
U.S. Pat. No. 4,395,328 (Hensley, Jr. et al.) discloses a process for the conversion of a hydrocarbon stream containing asphaltenes and a substantial amounts of metals, comprising contacting the stream (in the presence of hydrogen) with a catalyst present in one or more fixed or ebullating beds, the catalyst comprising at least one metal which may be a Group VIB or Group VIII metal, an oxide of phosphorus, and an alumina support, where the alumina support material initially had at least 0.8 cc/gm of TPV in pores having diameters of 0-1200A, and at least 0.1 cc/gm of TPV is in pores having diameters of 1200-50,000A, and the support material was heated with steam to increase the average pore diameter of the catalyst support material. Hensley, Jr. et al. ('328) is distinguished from the instant invention in that its catalyst requires a minimum pore volume in pores with diameters &gt;1200A to be 0.10 cc/g, whereas the metals-free supports of the catalysts employed in the instant invention typically contain 0.02 to 0.08 cc/g in this region. In addition, it requires the steaming of a support containing not less than 5 wt % phosphorus oxides prior to metals impregnation, whereas the supports for the catalysts employed in the instant invention are formed without phosphorus, said element being added in the range of 0.0 to 2.0 wt % P.sub.2 O.sub.5 during the metals impregnation step;
U.S. Pat. No. 4,341,625 (Tamm) discloses a process for hydrodesulfurizing a metal-containing hydrocarbon feedstock which comprises contacting the feedstock with a catalyst comprising at least one hydrogenation agent (i.e. Group VIB or Group VIII metals, or combinations thereof) on a porous support, the catalyst being further characterized by having a TPV of 0.5-1.1 cc/g with at least 70% TPV in pores having diameters of 80-150A and less than 3% TPV in pores having diameters greater than 1000A. Tamm ('625) is distinguished from the instant invention in that the catalyst of Tamm restricts the pore volume in pores with diameters .gtoreq.1000A to less than 3% TPV, whereas the catalyst employed in the instant invention typically contain 4% to 10% TPV in this region;
U.S. Pat. No. 4,328,127 (Angevine et al.) discloses a catalyst composition for use in the hydrodemetalation-desulfurization of residual petroleum oils, the catalyst comprising a hydrogenating component (i.e. Group VI or Group VIII metals, or combinations thereof) on a porous support, and being further characterized by having a TPV of 0.45-1.5 cc/g with 40-75% TPV in pores having diameters of 150-200A, and up to 5% TPV in pores having diameters of greater than 500A. Angevine is distinguished from the instant invention in that Angevine requires that the catalyst pore volume in pores with diameters between 150A to 200A be 40-75% TPV, whereas the catalyst employed in the instant invention typically contains from 3% to 9% TPV in this region.
U.S. Pat. No. 4,309,278 (Sawyer) discloses a process for the hydroconversion of a hydrocarbon feedstock comprising contacting the feedstock with hydrogen and a catalyst in a fixed bed, moving bed, ebullating bed, slurry, disperse phase, or fluidized bed reactor, where the catalyst comprises a hydrogenation component (i.e. Group VIB or Group VIII metals) on a porous support, and is further characterized by having a TPV of 1.0-2.5 cc/g with no more than 0.05-0.20 cc/g of TPV in pores having diameters of greater than 400A. Sawyer is distinguished from the instant invention in that Sawyer requires a catalyst TPV between 1.0 and 2.5 cc/g for the "beaded" catalyst support, whereas the supports of the catalysts employed in the instant invention have TPVp's .ltoreq.0.9 cc/g. In addition, the catalyst employed in the instant invention uses an "extruded" rather than "beaded" support;
U.S. Pat. No. 4,306,965 (Hensley, Jr. et al.) discloses a process for the hydrotreatment of a hydrocarbon stream comprising contacting the stream with hydrogen and a catalyst, the catalyst comprising chromium, molybdenum, and at least one Group VIII metal on a porous support, and further characterized by having a TPV of 0.4-0.8 cc/g with 0-50% TPV in pores having diameters smaller than 50A, 30-80% TPV in pores having diameters of 50-100A, 0-50% TPV in pores having diameters of 100-150A, and 0-20% TPV in pores having diameters greater than 150A. Hensley, Jr. et al. ('965) is distinguished from the instant invention in that Hensley, Jr., requires that 30% to 80% catalyst TPV be in pores with diameters between 50A to 100A, whereas the catalysts employed in the instant invention typically contain 6% to 11% TPV in this range. Furthermore, it also requires that 0% to 50% TPV be in pores with diameters between 100A to 150A, whereas the catalysts of the instant invention typically contain from 66% to 81% TPV in this region. Hensley, Fr. et al. ('965) also requires the presence of chromium on the catalyst which the instant invention does not;
U.S. Pat. No. 4,297,242 (Hensley, Jr. et al.) discloses a b 2-stage process for the catalystic hydrotreatment of hydrocarbon streams containing metals and sulfur compounds, the process comprising: (i) first contacting the feedstock with hydrogen and a demetalation catalyst comprising a Group VIB and/or Group VIII metal; and (ii) thereafter reacting the effluent with a catalyst consisting essentially of at least one Group VIB metal on a porous support, and having a TPV of 0.4-0.9 cc/g and a pore size distribution such that pores having diameters of 50-80A constitute less than 40% TPV, pores having diameters of 80-100A constitute 15-65% TPV, pores having diameters of 100-130A constitute 10-50% TPV, and pores having diameters of greater than 130A constitute less than 15% TPV. Hensley, Jr. ('242) is distinguished from the instant invention in that it requires a two-stage process to achieve the disclosed levels of hydrotreatment, whereas the instant invention achieves the disclosed levels of hydrotreatment in a single stage process and is also suitable for use in a multistage process. In addition, Hensley, Jr. ('242) is distinguished from the instant invention in that it restricts the pore volume in pores with diameters .gtoreq.130A to less than 15% TPV, whereas the catalysts employed in the instant invention typically contain from 35% to 50% in this region;
U.S. Pat. No. 4,089,774 (Oleck et al.) discloses a process for the demetalation and desulfurization of a hydrocarbon oil comprising contacting the oil with hydrogen and a catalyst, the catalyst comprising a Group VIB metal and an iron group metal (i.e. iron, cobalt, or nickel) on a porous support, and having a TPV of 0.4-0.65 cc/g with at least 10% TPV in pores having diameters of less than 30A, at least 45% TPV in pores having diameters of 30-150A, and at least 15% TPV in pores having diameters greater than 300A. Oleck is distinguished from the instant invention in that it requires that at least 15% catalyst TPV be in pores with diameters .gtoreq.300A, whereas the catalysts employed in the instant invention typically have 5% to 14% TPV in this region. In addition, Oleck requires the incorporation of Delta and/or Theta phase alumina, whereas the catalysts employed in the instant invention do not;
U.S. Pat. No. 4,082,695 (Rosinski et al.) discloses a catalyst for use in the demetalation and desulfurization of petroleum oils, the catalyst comprising a hydrogenating component (e.g. cobalt and molybdenum) on a porous support, and having a surface area of 110-150 m.sup.2 /g and pore size distribution such that at least 60% TPV is in pores having diameters of 100-200A and not less than 5% TPV is in pores having diameters greater than 500A. Rosinski et al. ('695) is distinguished from the instant invention in that it requires a relatively low surface area of 110 to 150 m.sup.2 /g, whereas the catalysts employed in the instant invention have surface areas in the range of 150 to 210 m.sup.2 /g. Furthermore, whereas Rosinski et al. ('695) specifies a broad micropore volume indicated by the criteria of at least 60% TPV in pores with diameters between 100A and 200A, the catalysts employed in the instant invention require 70% to 85% TPV in pores with diameters between 100A and 160A;
U.S. Pat. No. 4,066,574 (Tamm) discloses a catalyst composition useful in the hydrodesulfurization of a hydrocarbon feedstock containing organometallic compounds, the catalyst comprising Group VIB and Group VIII metal components on a porous support, and having a TPV of 0.5-1.1 cc/g with a pore diameter distribution such that at least 70% TPV is in pores of diameters of 80-150A and less than 3% TPV is in pores having diameters greater than 1000A. Tamm ('574) is distinguished from the instant invention in that it limits the catalyst pore volume of pores with diameters .gtoreq.1000A to less than 3% TPV, whereas the catalysts employed in the instant invention typically contain from 3% to 10% in this region;
U.S. Pat. No. 4,051,021 (Hamner) discloses a catalytic process for the hydrodesulfurization of a hydrocarbon feed which comprises contacting the feed with hydrogen and a catalyst, the catalyst comprising a Group VIB and Group VIII metal on a porous support, and having a TPV of 0.3-1.0 cc/g with a pore diameter distribution such that greater than 50% TPV is in pores of diameters of 70-160A, and pore diameters below 70A and above 160A are minimized. Hamner is distinguished from the instant invention in that the catalyst employed in the instant invention must have macropores constituting 5.5-22.0% TPV having diameters of greater than 250A, whereas in Hamner a catalyst having 10% TPV residing in pores having a diameter of greater than 200A is only marginally effective, with 0% TPV in diameters of greater than 200A being preferred. Thus Hamner discloses an essentially monomodal catalyst with no macroporosity;
U.S. Pat. No. 4,048,060 (Riley) discloses a two-stage process for hydrodesulfurizing a heavy hydrocarbon feed which comprises: (i) contacting the feed with hydrogen and a first catalyst to produce a first hydrodesulfurized hydrocarbon product, the first catalyst comprising a Group VIB and Group VIII metal on a porous support and having a mean pore diameter of 30-60A; and (ii) contacting the first hydrodesulfurized hydrocarbon product with hydrogen and a second catalyst under hydrodesulfurization conditions, the second catalyst comprising a Group VIB and Group VIII metal on a porous support and being further characterized by having a TPV of 0.45-1.50 cc/g with 0-0.5 cc/g of TPV in pores having diameters greater than 200A, 0-0.05 cc/g of TPV in pores having diameters below 120A, and at least 75% TPV in pores having diameters .+-.10A of a mean pore diameter of 140-190A. Riley ('060) is distinguished from the instant invention in that it requires a two-stage process to achieve the disclosed degree of hydrotreatment, whereas the instant invention achieves disclosed levels of hydrotreatment in a single stage process although it is also suitable for use in a multi-stage process. In addition, Riley ('060) requires a small pore catalyst in the first stage with a mean pore diameter of 30A to 60A, whereas the catalysts employed in the instant invention have median pore diameters of 120A to 130A. Riley ('060) also requires a large pore catalyst in the second stage with a pore volume of 0.0 to 0.05 cc/g in pores with diameters less than 120A, whereas the catalysts employed in the instant invention have 0.20 to 0.30 cc/g in this region;
U.S. Pat. No. 3,876,523 (Rosinski et al.) discloses a process for the demetalizing and desulfurizing of residual petroleum oil comprising contacting the oil with hydrogen and a catalyst, the catalyst comprising a Group VIB and Group VIII metal on a porous support and having a pore size distribution such that greater than 60% TPV is in pores having diameters of 100-200A, at least 5% TPV is in pores having diameters greater than 500A, and 10% TPV or less is in pores having diameters less than 40A, and the surface area of the catalyst is 40-150 m.sup.2 /g. Rosinski et al. ('523) is distinguished from the instant invention in that it requires a relatively low surface area of 40 to 150 m.sup.2 /g, whereas the catalysts employed in the instant invention require a surface area of 150 to 210 m.sup.2 /g;
U.S. Pat. No. 3,770,617 (Riley et al.) discloses a process for the desulfurization of a petroleum hydrocarbon feed comprising contacting the feed with hydrogen and a catalyst, the catalyst comprising a Group VIB or Group VIII metal on a porous support and having greater than 50% TPV in pores having diameters of 30-80A, less than 4% TPV in pores having diameters of 200-2000A, and at least 3% TPV in pores having diameters greater than 2000A. Riley et al. ('617) is distinguished from the instant invention in that it requires that greater than 50% TPV be in pores with diameters between 30A and 80A, whereas the catalysts employed in the instant invention typically have 2% to 3% TPV in this region; and
U.S. Pat. No. 3,692,698 (Riley et al.) discloses a catalyst useful in hydroprocessing of heavy feed stocks, the catalyst comprising a mixture of Group VIB and Group VIII metals on a porous support and having a pore size distribution such that a major portion of its TPV is in pores of diameters ranging from 30-80A, less than 4% TPV is in pores of diameters of 200-2000A, and at least 3% TPV is in pores of diameters greater than 2000A. Riley et al. ('698) is distinguished from the instant invention in that it requires that the major portion of TPV be in pores with diameters between 30A and 80A, whereas the catalysts employed in the instant invention have the major portion of TPV in pores with diameters between 100A and 160A.